In every vehicular air conditioning system there is a plurality of sections of flexible hosing. These hose sections connect together, in a single system, the various system components including a compressor, condenser, etc. A coupling member is required at each hose end to allow the hose to be secured to the various components between which it extends. The coupling member will usually include one portion of a threaded fastener such as a captured, rotatable nut, or similar means of connection to a system component. The usual manner of securing the flexible hose to the coupling member is to utilize a coupling member having two concentric cylindrical portions spaced from one another by about the approximate thickness of the hose. One of these concentric members includes a radial extending flange securing it to the other member. The inner concentric member includes a throughbore having a diameter approximately equal to the inside diameter of the hose to which it is being coupled. During assembly, the hose is slipped over the inner concentric cylinder and the outer concentric cylinder is then crimped down upon the hose and the other member to form a fluid-type joint.
A typical coupling of this type is shown in U.S. Pat. No. 5,044,671, which is assigned to the assignee of the present invention. As will be noted from the '671 patent, the outer concentric member or sleeve of the coupling is in the shape of a cup such that it includes a radial flange extending radially inward toward the inner concentric tube. The flange includes a throughbore. To assemble the sleeve, the inner concentric member or tube is provided with annular locking ribs and the radial flange is then swaged onto the locking ribs of the tube. Alternatively, the inner tube may be upset, or otherwise provided with a radial shoulder, immediately adjacent and contiguous with both sides of the radial flange of the sleeve so as to provide an axial stop in both directions. In each case, the axial position of the two coupling components, i.e., the sleeve and the tube, is fixed relative to one another. It is not a fluid-tight seal and need not be since the sealing is done between the hose and the coupling member in the areas of the above-described crimp. It does require a number of metal forming operations on the same tube member, which in turn burdens product reliability concerns as well as adding to product cost.
Current technology for fabricating such a coupling includes the steps of (i) end forming the inner tube, (ii) shaving the tube with grooves forming the annular locking ribs to bite into the inside of the hose, (iii) attaching the crimp shell and locking it to the tube with a bead lock which is then formed on the tube, (iv) placing a metal insert inside the tube to keep the tube from collapsing when the hose is crimped or, alternatively, to place a temporary mandrel inside the tube during the crimping operation, and (v) crimping the shell and tube assembly onto the hose.
The process as described requires the purchase or fabrication of expensive metal inserts and crimp sleeves. If inserts are not used, then mandrel tooling must be fabricated depending on the hose configuration, thus requiring added expense. Further, the manner in which the sleeves are locked to the tube requires extensive end forming. The grooves and high surface finish needed on the tubes requires expensive shaving equipment and is a continual high cost maintenance item. Further, the sleeves lock to the tube in this manner providing no positive assurance that the hose and sleeve may not be rotated relative to the tube.
The present invention is directed toward eliminating the need for anything more than a single upsetting operation coupled with the conventional crimping step thereby improving product reliability and reducing product cost.